1. Field of the Invention
The present invention relates to aqeuous baking varnishes suitable for coating conductors such as electric wires.
2. Description of the Prior Art
Hitherto, almost all baking varnishes and particularly wire enamels are the so-called solvent type varnishes wherein an organic solvent such as cresol, xylene or naphtha is used. These varnishes have the defects that the solvent and gases of decomposition disperse in the air in the production of insulated wires causing air pollution and the cost is high because the solvent should be completely incinerated by a combustion furnace. Further, the working environment in the production and the use of these organic solvent-type varnishes is very bad due to their bad smell and fire is always a danger because the solvents are inflammable. Recently, it is particularly desired to obtain wire enamels which do not have such defects creating a poor environment.
Although aqueous varnishes have been suggested as harmless wire enamels, they are not suitable since these aqueous baking varnishes do not have a low viscosity, a high concentration and a good film-forming property.